1 post tagged “geomorphology”
01 June 2009 Anchorage to Dutch Harbor, Unalaska Island, Alaska
PRIBILOF CANYON SEAFLOOR MAPPING EXPEDITION 2009
During our submarine expedition to the Bering Sea Caynons in 2007, we conducted 14 dives in Pribilof Canyon and 4 ROV surveys. We distributed our dive effort around the canyons at roughly equidistant intervals, to cover the depth ranges reachable in the deepworker submarines -- a maximum of 630 meters. The ROV could reach 1,100 meters. At that time, we navigated using the best available bathymetric (seafloor depth) information available.
Most of that data was based on relatively crude surveys from the 1960's, making it difficult to plan dives to precisely hit our depth and seafloor feature targets. OK, we were essentially "flying blind"! Our current mission is to map the canyons for purposes of future submarine research navigation and for many other purposes.
Pribilof Canyon and the connected Pribilof Domain waters surrounding the Pribilof Island Archipelago are recognized for their unique, highly productive characteristics by scientists in many disciplines --- geologists, fisheries biologists, oceanographers, benthic ecologists, foodweb specialists -- concur that the region's physical and biotic attributes are outstanding relative to the shelf break and shelf regions nearby. How unique and quantifying facets of the canyon geo-bio setting are challenges we continue to address.
Since so many marine scientific disciplines rely intimately upon modelling, and modelling requires a fundamental understanding of the geomorphology of the canyons, Dr. Dave Scholl and I underscored the importance of obtaining fine scale bathymetric data for the canyon system during our address at the Marine Science Symposium (Anchorage, January 2008). Dave, who first mapped the canyons with Dave Hopkins in the late 1950s, was startled to find that very little mapping effort has been conducted in that area in nearly 50 years!
Finally, a team with the right stuff has been assembled to map
the canyon.
St. Paul Islander, Candace Stepetin and I are focusing on biogeographical exploration of Pribilof Canyon. We will be examining areas already surveyed visually by submarine and ROV in previous years to observe the depth profiles, geomorphology of the area, and to ascertain whether the backscatter component of the sonar returns being used on this survey are capable of detecting seafloor features documented by sub.
The team is gathered in Anchorage on weather hold ... awaiting our flight to Cold Bay and westward to Dutch Harbor this afternoon.
